Engines use injectors to introduce fuel into the combustion chambers of the engine. The injectors may be hydraulically or mechanically actuated with mechanical, hydraulic, or electrical control of fuel delivery. Machines that use these engines may be operated in less than ideal atmospheric conditions such as at high altitudes or in cold weather. Under these conditions, particularly cold conditions, an engine may have trouble maintaining the temperature required to sustain combustion of the injected fuel. Repeated failed attempts to start an engine in cold conditions may result in excessive wear of the engine.
One way to improve starting and/or operation in cold conditions is to introduce a starting fluid, in addition to a normal fuel, into the engine to assist in starting the engine. This starting fluid is a highly flammable liquid that may allow for a higher combustion temperature during cold start conditions and may facilitate operation of an engine that might not otherwise start.
One system for introducing starting fluid into an engine is described in U.S. Pat. No. 5,388,553 (the '553 patent), issued to Burke et al. on Feb. 14, 1995. The '533 patent describes a system that introduces an ether mixture into an engine when an engine coolant temperature is below a predetermined temperature and when an engine speed is within a predetermined speed range. Specifically, the system of the '533 patent begins to introduce ether into the engine when the engine coolant temperature is below 40° F. and when the engine speed is greater than 80 RPM and less than 1800 RPM. The system of the '553 patent stops introducing ether when the engine speed exceeds 1800 RPM regardless of engine coolant temperature. The system of the '553 patent does not introduce ether into the engine if the engine coolant temperature is initially greater than 40° F., regardless of engine speed.
While prior art systems may assist the starting of an engine in cold conditions, that may be problematic when used at high altitudes. That is, due to the reduced oxygen at higher altitudes, combustion of both starting fluid and normal fuel still may not be sustainable, and the prior art systems do little to accommodate the lack of oxygen.
The disclosed fuel control system is directed to improving prior art systems.